<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <div class="main">
        <div class="test">
            <button>点我</button>
        </div>
    </div>
</body>
<script src="./js/utils.js"></script>
<script src="./js/index.js"></script>
<script>

    e(".main", () => {
        alert(2)
    })

    e(".test", (e) => {
        e.stopPropagation();
        alert(3)
    })

    e("button", (e) => {
      
        alert(1)
    })
</script>

</html>